Heartbeat
by kenzcraw
Summary: Alex's heartbeat keeps Kara grounded. It keeps her focused. Until she can't hear it anymore. Inspired by 2x19 promo.p


**A/N: Guys... I am so nervous for the coming Supergirl episode. So, so nervous. I love Alex to death and I am not looking forward to seeing her in such bad shape. That promo broke my heart so... I'm gonna be a wreck when I actually watch the episode. I know it.**

 **So, I wrote this thing. Inspired by the promo. I've always kinda had this idea that Kara knows everyone's heartbeats, especially Alex's. And I always thought she probably checks in on Alex just by listening for her heartbeat. I never really had an excuse to write about it, though, until that stupid promo that I never should have watched.**

 **I might expand on this. Let me know if I should. And in the meantime, let's all agree to brace ourselves not only for "Alex," but for the end of season 2. It's gonna be a doozy. Love you all!**

I had Alex's heartbeat memorized since the day I arrived on Earth. Since the moment I met her. I can pick it out over every single beat in the city without even trying. I know how it pounds with adrenaline and excitement during a mission. I tease her about how it thuds during particularly intense episodes of Game of Thrones. I know how it slows when she falls asleep, curled up on the couch next to me, with her head cushioned on my lap. I know the difference between how it stutters with fear – mostly for me – and how it stutters when Maggie walks in the room.

I know my sister's heartbeat. Every part of it.

So at first, I can't understand the dull, fading beat I'm straining to hear as I hurtle through the air toward the building Winn had finally tracked down. It's slow, it's muffled, and as I slice through the roof and land on the concrete floor, I have absolutely no idea what could possibly be making that noise.

Not until I see my sister, limp and unconscious, floating in that tank. For a moment, I stare, uncomprehendingly. That's not her heartbeat. I know her heartbeat, and that's not it. I've never heard that before. It can't be her heart that's slowing, fading… Dying.

 _Ba-dum… Ba-dum... Silence._

There's a muffled crashing behind me, Maggie's voice yelling, but I'm already lunging toward the tank. My fist crashes through it like butter, and I catch Alex in my arms as the glass shatters and water cascades and breaks around me. I cradle her to me, lower her to the floor, and Maggie is screaming her name behind me and all I can do is hold her and be swallowed by the silence pulsing in my straining ears.

"Kara, Kara, is she breathing?"

 _Oh God, she's so pale, her lips are blue, and her heart is silent. God, I don't know what to do. What do I do?_

"Kara! Is she breathing?"

I can't hear her heart, I can't hear it. I need to hear it, it needs to beat.

" _Kara!"_

Maggie's voice shakes me enough to look up from my sister's white face and into the eyes of the man who took her. He's across the room, grinning and shrugging his shoulders. Almost like he's saying "Whoops! My bad!"

I shoot to my feet just as Maggie slides to her knees next to me in time to take Alex in her arms. Heart burning with that familiar and hated rage, I hurl myself at him with a scream tearing from my throat. His eyes widen and he takes one step back before my hands are fisted in his shirt and he's flying against the wall.

"My sister! _That's my sister_!" I'm screaming, heat is burning in my eyes but I hold it back. It takes everything I have to not let the heat explode and incinerate him, the way my heart feels like it's being ripped out and set alight all at the same time.

I won't let him burn the way I'm burning now. Not yet. He doesn't get off that easy.

I snatch him up from the floor and heave him across the room again. Bones break in his body on impact but I don't care, I don't care. His heart is beating, beating erratic and heavy, and my sister's isn't. There's a dull _glub glub glub_ from where I left Maggie with her, and somewhere in my racing, uncomprehending mind, I know Maggie is forcing her heart to beat, forcing her lungs to breathe.

But that's not my sister's heartbeat. I know what her heart sounds like when she's alive, and now I know what it sounds like when she dies.

I thought the sound of Krypton dying was the most haunting thing I would ever hear. I was wrong.

I yank him up and know a sick pleasure at the sight of the blood dripping from his mouth, the panic in his eyes, the whimper that escapes when I raise my fist and bring it crashing across his face. His heart is pounding away, strong and alive and my sister's isn't. How is that fair? How am I supposed to live with that?

I _can't_.

I hit him again and teeth fly out of his mouth.

Behind me, Maggie is sobbing and Alex's heart is a forced _glub glub glub_.

I hit him again, and his cheekbone shatters around my knuckles and he shrieks. He's saying something to me – begging, I think – and I hit him again, again, again. Each one with a name attached to it. _Alex, Alex, Alex, Alex._

My whole world, ripped from me. _Again_.

My knees give out and I drag him down to the floor with me, leaning over him, still throwing my fist against his cheek. _Crunch, crunch, crunch_.

 _Glub glub glub. Alex, Alex, Alex, Alex._

I'm screaming, the heat is building behind my eyes and I don't want to hold it back anymore. I don't think I can. He's conscious enough to see the red ringing my eyes, enough to hold his trembling hands out to me, a muffled "please," whispered through bloody lips.

 _Glub glub… Ba-dum, ba-dum, ba-dum._

It's wild, it's erratic and pained, but I know that beat. It's suddenly crashing in my ears and I jerk my head around to see Maggie, in hysterics, cradling my sister, brushing locks of soaked hair away from her face. But she's smiling. And saying something that sounds a lot like "hey, hey, you're okay, just breathe. Breathe, Alex."

And _Alex_. My eyes lock on her.

My sister is coughing, gasping and _breathing_. Desperate, hacking breaths. _Ba-dum, ba-dum, ba-dum._ That beat is going strong now, familiar and grounding and beautiful.

My fingers go limp around his shirt and I'm crawling over to them on trembling hands and knees, eyes blurred not by heat vision, but by tears. I'm dimly aware of uniformed figures - DEO or NCPD, I don't know and don't care - surging around us, voices yelling and weapons flashing. Cuffing the barely conscious man behind me. I ignore them and drag myself the remaining feet to where Maggie is holding Alex, helping her sit up a little so she can breathe.

Maggie looks up at me as I get there, holds a hand out to me and brushes my hair away from my face. "It's okay, Little Danvers. She's okay."

I can barely hear her over the thudding in my ears, the beat that I'm still not sure I'm hearing. I reach for Alex, and her hand comes up to my face, brushing away a tear.

"I'm okay, I'm okay." Her voice, raspy and rough as it is, is like a balm. Soothing what remains of the burning rage and grief that had my eyes searing just seconds ago. "Kara, I'm okay."

I try to choke out her name but it ends up being a whimpered sob. I squeeze my arms around her until she's sandwiched between Maggie and I. She nestles her face in the crook of my neck, still gasping out ragged breaths against my skin. Rasping my name and Maggie's in whispers I can barely hear so I doubt Maggie can. I press my face against her soaking wet hair and squeeze my eyes shut, straining with everything in me to hear her heartbeat. Listening until it's the only thing I can hear.

 _Ba-dum, ba-dum, ba-dum, ba-dum._


End file.
